Pertussis is a respiratory tract infection caused by Bordetella Pertussis and can be a life threatening disease especially for young infants. It can be seen at any age. Since Pertussis can be mortal for unimmunized infants, a new immunization programme known as Cocooning Strategy is started. Herein, we report a newborn with persistant leukemoid reaction diagnosed as Pertussis and we aimed to discuss the case in the light of current literature.